1. Field of the Invention
The present invention relates to an HVAC system for an automotive vehicle and more specifically, automatically operating the HVAC fan speed during the vehicle's warm-up stage based on occupancy of the vehicle.
2. Description of Related Art
During a vehicle's warm-up stage in a vehicle having a conventional HVAC system, an occupant must manually set both the heating/cooling air temperature and HVAC fan settings to obtain an optimum comfort level inside the vehicle. During the vehicle's warm-up stage, however, the heating/cooling air temperature coming from the heating/cooling vents is initially at an uncomfortably cold temperature. Thus, if the occupant immediately sets the HVAC fan on maximum speed, cold air will blow into the inside of the vehicle, which initially causes the temperature inside the vehicle to decrease. This phenomenon is illustrated in the graph in FIG. 8, which shows the occupant comfort level of the occupant during the vehicle's warm-up stage over time. The graph shows that with the heating/cooling air temperature set at maximum and the HVAC fan set at maximum speed, the occupant comfort level inside the vehicle initially decreases. In other words, the occupant experiences an initial decrease in temperature inside the vehicle before the temperature gradually increases. Therefore, the occupant will preferably wait until the heating/cooling air temperature is warm before turning the HVAC fan to maximum speed. If on the other hand, the occupant is not in the vehicle during the warm-up stage the occupant would prefer to set the HVAC fan on maximum speed so that as the heating/cooling air temperature increases the temperature inside of the vehicle quickly increases. Thus, the occupant has to manually set the HVAC fan to maximum speed before departing the vehicle.
The present invention overcomes the need for the occupant to manually set the HVAC fan speed during the vehicle's warm-up stage by automatically operating the HVAC fan speed based on vehicle occupancy.